Knowledge of the orientation of an object (for example, an aircraft or boat or wireless communications base station antenna) may be desired in many situations. For example, in order to provide radio signals throughout a defined area, antennas in cellular wireless communications systems may be oriented to face a specific direction (referred to as “azimuth”) relative to true north, to be inclined at a specific downward angle (referred to as “tilt” or “pitch”) with respect to the horizontal in the plane of the azimuth, and to be vertically aligned (referred to as “roll” or “skew”) with respect to the horizontal in the plane of the azimuth. Undesired changes in azimuth, tilt, and/or roll can detrimentally affect the coverage of antennas. The more accurate the installation of the antennas, the better the network performance that may be achieved within the area served by the antennas.
An antenna's azimuth, tilt, and/or roll can change over time, due to for example the presence of high winds, corrosion, poor initial installation, vibration, hurricanes, tornadoes, earthquakes, or other factors. Wireless service providers may conduct periodic audits of their communication antennas to ensure that each antenna has not deviated significantly from its desired azimuth, tilt, and/or roll directions. Wireless service providers may hire third-party tower companies to perform audits and to make any necessary adjustments to maintain the desired alignment. Such audits, however, may be labor intensive and dangerous, often requiring certified tower climbers to physically inspect each antenna, and to take appropriate measurements to determine deviations from the desired positioning. This can become even more time consuming if many towers are affected as a result of a hurricane or storm, as the antennas may have to be checked one-by-one to determine which towers have been affected.
Some conventional techniques for determining antenna alignment may use magnetometers, accelerometers, gyroscopes, and/or GPS (global positioning system) receivers to determine the current alignment of an antenna and/or to detect changes in antenna alignment over time. However, such methods may lack sufficient accuracy for antenna alignment applications. For example, magnetometers may be subject to local distortions in the earth's magnetic field, and may not sufficiently address the antenna's geolocation (i.e., latitude, longitude, and altitude).